Superconducting Qubits: Latest IBM, Google & Rigetti Developments
Latest superconducting qubit news: IBM Quantum, Google Willow chip, Rigetti Novera. Cryogenic systems, error correction & quantum supremacy updates.
Superconducting qubits represent the most commercially advanced quantum computing technology, powering systems from IBM, Google, and Rigetti. These quantum processors leverage Josephson junctions—superconducting circuits that create non-linear inductance—to generate controllable quantum states at temperatures near absolute zero (15-20 millikelvin).
The dominant superconducting qubit design, the transmon qubit, balances coherence time and control simplicity by reducing sensitivity to charge noise. Recent breakthroughs include Google's Willow chip achieving below-threshold quantum error correction, demonstrating that increasing qubit count can actually reduce errors—a critical milestone for fault-tolerant quantum computing. IBM continues scaling its Heron processor architecture toward 1,000+ qubit systems while improving gate fidelities above 99.5%.
India's National Quantum Mission & Superconducting Qubits
India's National Quantum Mission (NQM), approved by the Union Cabinet on 19 April 2023 with an allocation of ₹6,003.65 crore for eight years (2023-2031), prioritizes superconducting qubit development under its Quantum Computing Thematic Hub. The Foundation for QC Innovation at IISc Bengaluru serves as the lead institution for this hub, working with IIT Delhi, IIT Bombay, TIFR Mumbai, and other institutions. The Tata Institute of Fundamental Research (TIFR) in Mumbai has established dilution refrigeration laboratories capable of operating at ultra-low temperatures to support superconducting qubit research. In August 2024, DRDO scientists from the Young Scientists Laboratory for Quantum Technologies (DYSL-QT), in collaboration with TIFR and TCS, completed end-to-end testing of a 6-qubit superconducting quantum processor with a novel ring-resonator design. This system includes a cloud-based interface developed by TCS for submitting quantum circuits and receiving computed results.
The NQM targets developing intermediate-scale quantum computers with 50-1000 physical qubits in eight years using various platforms including superconducting and photonic technology. Indigenous development of quantum fabrication facilities is underway, with IISc Bengaluru and IIT Bombay establishing quantum computing fabrication facilities under a ₹720 crore investment announced in November 2025. These facilities will support superconducting, photonic, and spin qubit technologies.
Key Advantages
Key advantages of superconducting qubits include nanosecond gate speeds enabling rapid algorithm execution, established semiconductor fabrication processes supporting manufacturing scalability, and a strong cryogenic infrastructure ecosystem. Current challenges include decoherence times (100-300 microseconds) that remain shorter than trapped-ion alternatives, error rates requiring extensive quantum error correction overhead, and cryogenic operation demands for specialized infrastructure.
Major Players
Major global players include IBM Quantum with cloud-accessible systems (Eagle, Osprey, Condor processors), Google Quantum AI focusing on error correction and quantum supremacy demonstrations, and Rigetti Computing offering hybrid quantum-classical systems. In India, the Foundation for QC Innovation at IISc, TIFR Mumbai, and IIT Bombay are building national capability with NQM support, while startups including QpiAI India are working on superconducting quantum computers.
quantum-computingThinking About Selling Your Bitcoin? Nearly 50% of Holders Might Be Too.
By Alex Carchidi – Apr 10, 2026 at 1:30AM ESTKey PointsBitcoin is in the midst of a long downward trend.Many of its most ardent holders are sitting on losses.There's an opportunity here if you can stomach it. Bitcoin (BTC +1.61%) is down by 6% over the last 12 months and 43% from its all-time high of just above $126,000, set in October 2025. If you're thinking of selling it after such a prolonged and steep decline, you aren't alone. In fact, at its current price, about 47% of all Bitcoin in circulation is now held at a loss. That's a vast amount of pain for investors to be carrying, and the urge to cut losses is natural. But selling into the market's fear has historically been a losing strategy with this asset far more often than not. Here's what the data says about what you should do. Image source: Getty Images. Even some evangelists are cracking One important detail is that Bitcoin's long-term holders, which includes all kinds of wallets with balances unmoved for six months or more, are bearing the heaviest burden. Over 4.6 million of their coins, roughly 30% of their holdings, are now underwater, the largest share since 2023. Some are selling at their deepest losses in three years. So if you're suddenly feeling a lot less convinced about the investment thesis for Bitcoin, know that some of its most loyal and longtime boosters are now feeling the same doubt. Fresh anxiety arrived in the last week of March when Alphabet's Google Quantum AI published a new paper outlining a smattering of theoretical attack paths against the cryptography underpinning Bitcoin, including scenarios where quantum computers could crack its encryption significantly faster than previously estimated. The practical threat from such quantum computers still remains at least a handful of years away, but the news compounds the ongoing unease about the coin, stemming from geopolitical conflict and a very questionable macro environment. ExpandCRYPTO: BTCBitcoinToday's Change(1.61%) $1144.65Current
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quantum-computingUnleashing the Advantage of Quantum AI
As experimental capabilities advance rapidly, the quantum computing community faces a critical elephant in the room: What will these quantum machines eventually be useful for? Will they deliver the promised broad societal impact, or will they remain highly specialized devices for exotic tasks known only to the experts? The elephant in the room Despite decades of effort, conclusive evidence of large quantum advantage in real-world applications remains confined to a few niche domains, such as simulating quantum materials and cryptanalysis. These problems are either inherently quantum to begin with, or they possess specialized mathematical structure that quantum algorithms can easily exploit. But it seems unlikely that such structures appear broadly in everyday life. Indeed, most applications of modern computation hinge on the processing of massive, noisy classical data, generated at an unprecedented pace across society. That is the driving force behind the overwhelming success of machine learning and AI. Since the data originates from the macroscopic classical world, there is no obvious reason it should exhibit the delicate, specialized structures that quantum computers require. To playfully adapt Richard Feynman’s famous quote: We live in an effectively classical world, dammit, and maybe classical computers and AI already suffice for most of our problems. (For those unfamiliar, Feynman originally quipped: “Nature isn’t classical, dammit, and if you want to make a simulation of nature, you’d better make it quantum mechanical.”) The central challenge To truly unlock the power of a quantum computer, quantum algorithms typically need to access data in quantum superposition, processing many different samples simultaneously in different branches of the quantum multiverse. To use technical jargon, this is called querying a quantum oracle. But in reality, the classical data samples that we want to process are generated from everyday activities in a classical world, and we ca
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quantum-computingMicrostructure Predicts Qubit Coherence, Reducing Decoherence Loss by Two Orders of Magnitude
Vinayak P. Dravid and colleagues at Northwestern University present a new framework for understanding decoherence, the loss of quantum information, in superconducting quantum circuits. The framework separates measurable structural statistics from device geometry, offering a pathway towards predictive materials engineering for improved qubit performance. By defining classical and quantum microstructure and establishing a perturbative separability criterion, the research identifies five key areas influencing energy loss in transmon qubits. This framework, accompanied by a standardised reporting protocol, enables more robust and comparable results across different research laboratories. Decoherence sources isolated via channel-wise separable framework and reduced prescriptor analysis Transmon qubit coherence, a measure of how long quantum information is retained, now demonstrates a factor of two increase in achievable lifetimes compared to previous state-of-the-art devices. Surpassing a key threshold for scaling quantum computations, earlier limitations prevented reliable execution of complex algorithms due to rapid information loss. Previously, pinpointing the source of decoherence proved impossible because of simultaneous material and design alterations, creating a complex web of interconnected variables. Decoherence arises from interactions between the qubit and its environment, leading to the dissipation of quantum superposition and entanglement, the fundamental resources for quantum computation. These interactions can be broadly categorised into those originating from material defects within the qubit itself, and those arising from electromagnetic noise coupled to the qubit via its geometry and surrounding circuitry. Achieving sufficiently long coherence times, typically measured in microseconds, is paramount for performing meaningful quantum calculations. The newly formulated channel-wise separable framework allows independent measurement of structural characteri
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quantum-computingQuantum Computers Tackle Genome Assembly’s Toughest Puzzles
Scientists at the University of Cambridge and University of Oxford have developed a new approach to pangenome-guided sequence assembly, leveraging quantum optimisation techniques to address the computationally intensive challenges of genome reconstruction from sequencing data. Josh Cudby and colleagues tackle limitations inherent in repetitive genomic regions, where existing methods often falter due to reference bias and combinatorial complexity. Their research explores both quadratic unconstrained binary optimisation and a higher-order binary optimisation formulation, sharply reducing the number of required variables for complex calculations. By employing the Iterative-QAOA framework and a custom circuit compilation strategy, the team achieved promising results in simulations and on IBM quantum hardware, identifying optimal assemblies with a tiny fraction of candidate solutions. Pangenome assembly is established as a compelling application where quantum computing may offer a practical advantage soon. Quantum optimisation streamlines complex genome mapping Iterative-QAOA, a quantum algorithm akin to a guided search through many possibilities, proved central to overcoming computational hurdles in genome assembly. This algorithm belongs to a class of approximate optimisation algorithms designed to find near-optimal solutions to complex problems. Unlike classical algorithms that exhaustively search all possibilities, QAOA leverages quantum phenomena like superposition and entanglement to explore the solution space more efficiently. The Iterative-QAOA framework avoids painstakingly fine-tuning every parameter of the quantum process, instead employing a pre-defined schedule and iteratively refining its approach based on previous attempts. This iterative refinement is crucial for adapting to the specific characteristics of the genome assembly problem and improving solution quality over time. A custom circuit compilation strategy effectively streamlined the instructions se
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Cloudflare Accelerates Post-Quantum Roadmap to 2029 Amid Major Algorithmic Breakthroughs
Cloudflare Accelerates Post-Quantum Roadmap to 2029 Amid Major Algorithmic Breakthroughs Cloudflare has officially updated its post-quantum (PQ) security roadmap, shifting its target for full system-wide resilience to 2029. This acceleration is driven by recent and unexpected advancements in quantum factoring efficiency, which suggest that the window for migrating global internet infrastructure is closing faster than previously modeled. While the company enabled post-quantum encryption for all websites and APIs in 2022 to mitigate “harvest now, decrypt later” (HNDL) risks, the new roadmap prioritizes the much more complex challenge of post-quantum authentication. The urgency stems from two independent breakthroughs announced in late March and early April 2026. First, Google’s Quantum AI team published a whitepaper demonstrating a 20-fold reduction in the resources required to break ECDSA-256, the elliptic curve cryptography securing Bitcoin, Ethereum, and much of the public web. According to a recent Quantum Computing Report (QCR) Qnalysis, this development represents a “decryption threshold” that necessitates an immediate re-evaluation of the quantum threat to global blockchain infrastructure and decentralized finance. Verified via a zero-knowledge proof, Google’s optimized algorithm suggests that fewer than 500,000 physical qubits could be sufficient to crack these keys—a sharp decline from the 10 million qubits estimated just a few years ago. Parallel research from the Caltech-linked startup Oratomic has further compressed this timeline by focusing on neutral atom architectures. Oratomic’s research indicates that breaking RSA-2048 and P-256 could require as few as 10,000 reconfigurable atomic qubits. This efficiency is gained through a massive reduction in error-correction overhead; while superconducting systems typically require 1,000 physical qubits for a single logical qubit, neutral atom machines—which allow for dynamic, “high-rate” connectivity—may require o
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quantum-computingRigetti Is Growing Sales of Quantum Computers. That’s Good for the Stock. - Barron's
Rigetti Is Growing Sales of Quantum Computers. That’s Good for the Stock. Barron's
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quantum-computingAlice & Bob Secures €130M Funding, Employs 200+ People
Alice & Bob, a company developing fault tolerant quantum computing, is unveiling a refreshed brand identity as it expands from a research startup to a growing deeptech firm. The Paris and Boston-based company has secured €130 million in funding and now employs over 200 people, building toward its goal of creating the first universal, fault-tolerant quantum computer. This evolution is reflected in a streamlined visual approach that retains the company’s signature “cat qubit” symbol while introducing a bolder design. “Quantum computing is one of the most technically advanced sectors in the world, yet brand has largely been an afterthought,” said Niccolo Coppola, Marketing Lead at Alice & Bob; the update aims to reinforce clarity as the company scales and attracts investment in a rapidly evolving industry. Alice & Bob’s Transition from Startup to Deeptech Company Founded in 2020, Alice & Bob is reshaping its public image to reflect a shift from foundational research toward commercial viability. The Paris and Boston-based firm revealed a revised brand identity that maintains its signature “cat qubit” imagery while adopting a more assertive visual presentation. The company’s move toward a more recognizable brand isn’t merely aesthetic; it’s a strategic effort to attract talent, forge partnerships, and secure long-term investment as the quantum field matures. Coppola further stated, “We’ve approached brand as a strategic asset from the outset, but it’s something you have to build consistently—this update is about reinforcing that clarity as we scale.” This rebranding follows a recent demonstration of the efficiency of their cat architecture, which reportedly reduces hardware requirements for large-scale quantum computers by up to 200 times compared to alternative methods. With a team exceeding 200 employees and guidance from Nobel Prize-winning researchers, Alice & Bob aims to establish itself as a leader in fault-tolerant quantum computing, and the up
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quantum-computingRigetti makes its Cepheus-1-108Q quantum computer available via its cloud platform and Amazon Braket - Data Center Dynamics
Rigetti makes its Cepheus-1-108Q quantum computer available via its cloud platform and Amazon Braket Data Center Dynamics
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quantum-computingQBoson Secures CNY 1 Billion ($145 Million USD) Series B for Photonic Quantum Hardware Scaling
QBoson Secures CNY 1 Billion ($145 Million USD) Series B for Photonic Quantum Hardware Scaling QBoson, a Beijing-based developer of photonic quantum hardware, has closed a Series B funding round totaling CNY 1 billion ($145 million). The capital injection was jointly led by a consortium of state-supported and institutional investors, including Beijing Financial Holdings Group, ICBC Capital, Beijing Chaoyang Shunxi Sci-Tech Innovation Equity Investment Fund, CMB International, Shenzhen Investment Holdings, and Addor Capital. The round also saw participation from Turing Asset Management, Dingxing Quantum, Bofu Fund, Guangdong Technology Financial Group, and Guangzhou Financial Holdings, alongside follow-on investments from more than a dozen existing shareholders. Since its founding in 2020, QBoson has focused on photonic quantum computing, a modality that utilizes photons as qubits to achieve information processing at room temperature with reduced requirements for extreme cryogenic cooling. The company currently maintains a product line of specialized quantum systems with scales of 100, 550, and 1,000 qubits. These systems are intended for non-universal, specialized optimization tasks rather than general-purpose fault-tolerant computing, catering to immediate industrial needs in sectors such as drug discovery, finance, and power grid management. Operational Infrastructure and Production Goals A primary objective for this funding is the optimization of QBoson’s Shenzhen-based quantum computer factory, which began operations in November 2025. The company plans to establish a pilot production line for quantum computing chips to standardize manufacturing processes and improve hardware reliability. Target AreaImplementation GoalChip FabricationEstablishment of a dedicated pilot production line for photonic chips.Factory OperationsScaling China’s first large-scale quantum computer assembly facility in Shenzhen.System StabilityDeployment of AI-driven control systems for 7×16
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quantum-computingControls Developed to Reshape Quantum Arrow of Time
Insider Brief Researchers reported in Physical Review X the development of quantum control protocols that can suppress or invert the “arrow of time” in quantum systems, enabling processes that appear to run backward. The approach uses measurement and feedback to engineer time-reversed trajectories, allowing scientists to counteract or amplify disturbances and reshape how quantum systems evolve. The work points to practical applications including extracting energy from quantum measurements, improving quantum state preparation, and potential implementation in superconducting qubit systems. Image: Los Alamos National Laboratory PRESS RELEASE — In new research published in Physical Review X, scientists have designed quantum control protocols that generate processes more consistent with time flowing backward than forward. The protocols — techniques to control quantum systems — modify a quantum system’s “arrow of time,” the concept of time as moving in one forward direction. The work opens up possibilities for energy extraction from quantum systems and for quantum state preparation. A quantum system, such as a collection of qubits, is governed by the laws of quantum mechanics. The team’s control protocols can prevent the emergence of the arrow of time in a quantum system or even invert its direction — that is, cause quantum time to appear to flow in reverse. As an application of their research, the team leveraged their control protocols to design a measurement engine that extracts energy from quantum measurements performed on the system. “Unlike phenomena we observe around us, at the microscopic level most fundamental laws of physics see forward and backward movement in time as physically possible,” said Los Alamos National Laboratory physicist Luis Pedro García-Pintos. “In other words, those laws of physics are symmetrical under time reversal; the equations work just as well if you reverse time. For quantum systems, which operate at that microscopic level, the tools
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quantum-computingRigetti Announces General Availability of 108-Qubit System - The Quantum Insider
Rigetti Announces General Availability of 108-Qubit System The Quantum Insider
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quantum-computingRigetti Computing Stock Jumps. Why Its Most Powerful Quantum System Has Wall Street Excited. - Barron's
Rigetti Computing Stock Jumps. Why Its Most Powerful Quantum System Has Wall Street Excited. Barron's
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quantum-computingHere’s Why Rigetti Computing Stock (RGTI) Is Soaring Today - TipRanks
Here’s Why Rigetti Computing Stock (RGTI) Is Soaring Today TipRanks
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quantum-computingRigetti Ships 108 Qubit Device.
Rigetti Computing has made its 108-qubit quantum computer, Cepheus-1-108Q, generally available to customers and partners through its Quantum Cloud Services platform and Amazon Braket. This new system represents the largest modular quantum computer to date, utilizing Rigetti’s chiplet-based architecture and tripling the qubit count of its previous generation. Cepheus-1-108Q currently achieves a 99.1% median two-qubit gate fidelity with a gate speed of approximately 60 nanoseconds, alongside a 99.9% median single-gate fidelity. “Cepheus-1-108Q is a milestone that validates our approach to scaling quantum computers,” said Dr. Subodh Kulkarni, Rigetti CEO, adding that the company’s architecture is enabling higher fidelity and higher qubit systems that will ultimately enable fault-tolerant quantum computing. Cepheus-1-108Q: 108-Qubit System & Modular Architecture Rigetti Computing’s unveiling of the Cepheus-1-108Q system marks a significant leap in quantum processor scale, boasting 108 qubits, the highest count currently available in a modular architecture. Unlike many approaches relying on monolithic silicon, Rigetti has constructed Cepheus-1-108Q from twelve interconnected 9-qubit chiplets, effectively tripling the qubit count and chiplet number from its prior 36-qubit system. This modular design is not simply about increasing qubit numbers; it’s a deliberate strategy to address the escalating challenges of maintaining fidelity as systems grow more complex. Rigetti is also releasing the hardware, making Cepheus-1-108Q accessible to researchers and developers through both the Rigetti Quantum Cloud Services platform and Amazon Braket, broadening access to this advanced quantum computing capability. Subodh Kulkarni, Rigetti CEO, emphasized the importance of this architectural validation. Several key engineering improvements underpin the system’s performance. Rigetti has focused on enhanced qubit and coupler design to accelerate two-qubit gates and improve fidelity, wh
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quantum-computing5 New Risks to Ethereum Just Surfaced. Is The Coin Still a Buy?
By Alex Carchidi – Apr 8, 2026 at 3:23AM ESTKey PointsNew research indicates that quantum computers might be able to crack the encryption protecting most cryptocurrencies sooner than anticipated.Ethereum was singled out as being especially vulnerable.However, there's already a plan in progress to mitigate these risks. According to a new paper released by Alphabet's Google Quantum AI group on March 30, there are five distinct ways that a future quantum computer could attack Ethereum (ETH +6.18%) by breaking its encryption. That certainly sounds alarming. If everything the new research says is true, would the coin still be a buy? Image source: Getty Images. The five risks the paper actually found Ethereum is, at its heart, a collection of software. That software is secured by encryption. The point of the encryption is to make it very difficult for an attacker to perform actions like stealing or spending someone else's coins. And in terms of the risk posed by potential attackers equipped with normal computers, the encryption is successful at that goal. The trouble is that quantum computers are, in theory, capable of breaking the encryption that Ethereum and most other blockchains use. In practice, no known quantum computers that actually exist are powerful enough to do that. But quantum computers are becoming more sophisticated all the time, and, per the research by Google Quantum AI, it's also possible to design the quantum circuits they use to be vastly more efficient at codebreaking. The research was co-authored with Ethereum Foundation researcher Justin Drake and Stanford cryptographer Dan Boneh. In short, their paper is essentially a coordinated disclosure between the people building the quantum computers and the people running the blockchain, which is why their words carry a lot of weight. The core finding is that with their newly discovered quantum circuits, breaking the cryptography securing Ethereum would require fewer than 500,000 physical qubits, which is in
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quantum-computingUnlocking a fast adiabatic CZ gate and exact residual $ZZ$ cancellation between fixed-frequency transmons using a floating tunable coupler
--> Quantum Physics arXiv:2604.05048 (quant-ph) [Submitted on 6 Apr 2026] Title:Unlocking a fast adiabatic CZ gate and exact residual $ZZ$ cancellation between fixed-frequency transmons using a floating tunable coupler Authors:Angela Q. Chen, Xian Wu, Sarah Strong, Stefano Poletto View a PDF of the paper titled Unlocking a fast adiabatic CZ gate and exact residual $ZZ$ cancellation between fixed-frequency transmons using a floating tunable coupler, by Angela Q. Chen and 3 other authors View PDF HTML (experimental) Abstract:Tunable couplers in superconducting qubit architectures enable strong qubit-qubit interactions for two-qubit gates while suppressing unwanted coupling during single-qubit operations. However, achieving low error rates for fast two-qubit gates remains challenging, as suppressing leakage and non-adiabatic errors typically requires specialized qubit, coupler, or pulse designs, often at the expense of an idling $ZZ=0$ condition. In this work, we demonstrate that a symmetric floating tunable coupler provides a natural platform for fast, high-fidelity adiabatic controlled-Z (CZ) gates. Its favorable energy-level structure eliminates the conventional trade-off between rapid conditional-phase accumulation and adiabatic evolution while preserving exact cancellation of residual $ZZ$ interaction at idling. This architecture exhibits intrinsic robustness to non-adiabatic transitions, even under simple flux modulation waveforms. To push performance at short gate durations, where maintaining adiabaticity becomes more challenging despite the favorable level structure, we introduce pulse-shaping techniques based on the instantaneous adiabatic factor that further suppress non-adiabatic errors. We experimentally realize a 24 ns adiabatic CZ gate with fidelity exceeding 99.9% and stable operation over several hours. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.05048 [quant-ph] (or arXiv:2604.05048v1 [quant-ph] for this version) https://doi.
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quantum-computingA superconducting quantum circuit single artificial atom maser
--> Quantum Physics arXiv:2604.05105 (quant-ph) [Submitted on 6 Apr 2026] Title:A superconducting quantum circuit single artificial atom maser Authors:Maria Mucci, Nicholas Hougland, Chun-Che Wang, Israa Yusuf, Chenxu Liu, David Pekker, Michael Hatridge View a PDF of the paper titled A superconducting quantum circuit single artificial atom maser, by Maria Mucci and 6 other authors View PDF HTML (experimental) Abstract:We demonstrate a circuit QED analog of an atomic micromaser that utilizes an artificial, multi level atom, pumped into a population-inverted state by a microwave tone, as the gain medium. Our demonstration is enabled by the flexibility of the circuit QED platform, which allowed us to precisely engineer the level-structure, coupling, and dissipation of the micromaser components. Our device shows rich physics and perhaps points to ways to use the recent developments in the domain of microwave quantum circuits to probe the domain of maser physics. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.05105 [quant-ph] (or arXiv:2604.05105v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2604.05105 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Chun-Che Wang [view email] [v1] Mon, 6 Apr 2026 19:10:03 UTC (12,382 KB) Full-text links: Access Paper: View a PDF of the paper titled A superconducting quantum circuit single artificial atom maser, by Maria Mucci and 6 other authorsView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph < prev | next > new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADSGoogle Scholar Semantic Scholar export BibTeX citation Loading... BibTeX formatted citation × loading... Data provided by: Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Co
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quantum-computingRigetti Releases 108-Qubit Cepheus-1-108Q System via Cloud Platforms
Rigetti Releases 108-Qubit Cepheus-1-108Q System via Cloud Platforms Rigetti Computing has announced the general availability of its Cepheus-1-108Q quantum computing system. The 108-qubit processor is accessible via the Rigetti Quantum Cloud Services (QCS) platform and Amazon Braket. This system represents a scaling of the company’s modular architecture, increasing the qubit count from its previous 36-qubit iteration. The deployment on Amazon Braket marks the first gate-based quantum device with over 100 qubits to be hosted on the AWS service. The architecture of the Cepheus-1-108Q consists of twelve interconnected 9-qubit chiplets. This modular approach allows for the tiling of multiple small-scale chips to form a larger processor, a method Rigetti uses to manage yield and complexity during fabrication. At launch, the system is reporting a 99.1% median two-qubit gate fidelity and a 99.9% median single-qubit fidelity. The system maintains gate speeds of approximately 60 nanoseconds, consistent with the characteristics of superconducting transmon qubits. Technical improvements in this generation include the use of Alternating-Bias Assisted Annealing, a fabrication technique designed to improve qubit frequency targeting and reduce defects on the chip. Rigetti also implemented upgraded control electronics intended to provide a higher signal-to-noise ratio for qubit readout. To mitigate coupling interactions that often emerge in systems exceeding 100 qubits, the company refined its tunable coupler designs, shifting the primary performance constraints toward coherence times. For quantum error correction (QEC) research, the system utilizes adiabatic CZ gates. Rigetti’s internal benchmarks on prototype systems have demonstrated CZ gate fidelities as high as 99.9% at 28 nanoseconds, and these gate schemes are currently being integrated into the 108-qubit production environment. The availability of these high-fidelity native gates is intended to allow researchers to compile
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